Galileo and Light
by ahiijny
Summary: In which Mio, Yukko, Mai, and Nano set out to experimentally determine the speed of light. They begin with the primitive lantern method. However, Yukko gets a bit too competitive with their lantern reaction times.
1. Mio and Yukko

**日常 ****- nichijou, Arawi Keiichi**

* * *

After discussing and clarifying things beforehand, the four girls had set out towards two different hilltops, the two of them conveniently almost exactly 10 kilometers apart.

Mio and Yukko are together in one pair, and they're heading towards the high hill in the southeast. Mai and Nano are the other pair, and they're heading towards the small mountain in the north. Everything had been worked out beforehand with Google Maps, so there's no chance of getting lost. Hopefully.

They're going to be staying at a relatively high altitude on a late October night for this experiment, so they're both well bundled up. Jackets and everything. Also, Yukko and Mio are both wearing backpacks, and Mio is carrying a bright electrical lantern. Mio's the one carrying it because, apparently, Yukko can't be trusted with carrying that kind of delicate apparatus. The lantern has one of those shutters that can rapidly open and close, which is vital for the experiment.

"Are we there yet?" asks Yukko.

Mio is focusing on the phone in her left hand. "Just about there," she says. "The distance is like only 2 digits."

"I wonder if Mai-chan and Nano-chan have arrived yet?" Yukko asks, looking north. "Let's phone them."

"There aren't any bars here," Mio says, pointing to her cell phone. "Besides, I thought we were going to do this the traditional way?"

"Traditional," Yukko says. "Feh. That lantern's electric, isn't it?"

"I meant the general concept," Mio says, shrugging. "Lanterns are trivial details. Electric or not, they do the same thing, don't they? Light."

"Feh," says Yukko.

"Okay, stop," Mio says. "We should be here."

Yukko takes a look around at the grassy hill they're standing on. "Ooh, I see. The rock."

"Mm," says Mio, looking at the giant rock. They had chosen this exact location because of how distinguishable the rock had looked from Google Satellite.

They set down their packs and start setting up camp. "Only 22 minutes until sunset," Mio says. "Let's set things up quickly."

"Mm," says Yukko. She sets down her pack and starts helping Mio set up the tent.

Soon, the sun is more or less on the horizon.

"I don't see them yet," Mio says, looking north west, squinting her eyes.

"Oh, give them some time," says Yukko. "Wait, first let me try something."

"Hm?" Mio turns to look at Yukko curiously. Yukko is lying flat on the ground on her front, facing the sunset. The sun's so close to the horizon now that it doesn't actually pain her eyes much to look directly at it.

Several seconds pass in silence.

"Oh, give it a minute," Yukko says. "It's not gonna happen for some time yet."

"Hm," Mio says, turning away. She sets down the lantern and flicks it on, making sure that the shutter is open. She turns it to face the mountain at which Mai and Nano should be arriving soon. Then, she takes out her stopwatch and tests it to make sure that it works.

00:00.00

00:00.62

00:01.19

00:01.68

00:02.19

00:02.63

00:03.05

00:03.38

00:03.70

"Okay, the stopwatch works," Mio says, nodding. She resets the timer and then sits down on the grass. "Do you want to time it, Yukko, or should I?"

"Um…" Yukko says. She's still lying down on the grass. "What's the other option?

"Controlling the lantern," says Mio.

"Dibs on the lantern!" Yukko shouts, still lying low on the ground.

"Okay," Mio says. She looks around. She still doesn't see the other pair's lantern yet. "So, as we decided previously, we're going to be observer A," she says. "So I guess we'll be timing first."

"All right!" Yukko says.

"Remember, we're taking turns, so sooner or later, we'll switch so that they have a chance to time too," Mio says. "I know this isn't how they did it originally, but I thought that this was a good idea because Mai-chan probably has the best reaction time out of all of us. If we gave her a chance, we'd probably get more accurate results."

"Hey!" Yukko says. "My reaction time's not too shabby either."

"Mm," Mio says dismissively, not taking sides.

"Heh," says Yukko.

About a minute passes in silence.

"Oi, Yukko," Mio starts, "do you remember—"

"Ah, ah, it's starting!" Yukko smiles, visibly excited.

"Huh?" Mio turns to look at Yukko.

"Hush, hush," Yukko says, waving her arm dismissively, not taking her eyes off the sunset.

The sky is pretty dark now. From Yukko's point of view, the sun is barely peaking off the horizon. It's slowly dropping lower and lower… and then none of the sun is showing anymore. It's now completely hidden behind the horizon.

Yukko immediately shoots up, standing on her tip-toes, peering at the horizon.

"Aha!" she shouts. "Two sunsets in one day! All right!" She pumps her fist in the air.

"Ah…" Mio says, sweat-dropping.

A few seconds pass in silence.

Mio speaks. "You know, there's actually a lot of mathematics involved in the explanation—"

"YOU WERE saying something, Mio-chan, something about the experiment?" Yukko says loudly, interrupting Mio.

Mio blinks. "Ah, right," she says. "Do you remember the procedure?"

"No, let's hear it," Yukko says, grinning.

Mio sighs in exasperation. "All right, come here," says Mio, gesturing to a spot on the ground next to the lantern. Mio reaches into her backpack and pulls out a notebook as Yukko seats herself.

"Let's have a look," Yukko grins, holding the notebook up to the lantern.

"Observer A is in command, as you remember," Mio says, looking at the mountain in the distance.

"That's us," Yukko confirms.

"That's us first," Mio corrects. "Remember, for the purpose of fairness, both of us will eventually be A at some point."

"Huh?" Yukko tilts her head. "That's just needlessly complicated."

"Yukko, you were the one so vehemently set on being observer A that we had to make this compromise."

"Oh." Yukko blinks. "Oh yeah!" she grins.

Mio continues. "In any case, step 0 says that when we arrive, we turn on the lantern and open the shutter, implying that we're ready to go."

"We _are_ ready to go," Yukko says, looking up towards the mountain in the distance. "It's them that's _not_ ready to go."

"Ah, don't worry about them," Mio says, waving her hand dismissively. "Also, it's the same thing for them: When B arrives, they turn on their lantern like us. Next, step 1. Once both parties are ready, A closes the shutter," Mio says, holding up a finger. "Next, when B sees us close our shutter, they close their shutter too."

"You remember all this from memory?" Yukko asks incredulously.

"Step 3: A opens their shutter and starts their timer." Mio holds up their stopwatch. "Step 4: As soon as B sees us open our shutter, they open their shutter too. And finally, step 5: We stop timing when we see the light from B. This is how Galileo first tried to measure the speed of light back in the 1600s."

"What was the year _exactly_?" asks Yukko.

"I don't remember," Mio says, shrugging.

"Why's 'c' the speed of light?" Yukko asks. "Why not 'h' or 'l' or something?"

"I don't know," says Mio.

"Ah…" says Yukko.

A few minutes pass.

"It's starting to really get cold," Yukko says, shivering a bit.

"Oh, man up," Mio says teasingly.

"Maybe I should've brought more layers," says Yukko.

In the distance, a small light blinks into existence, signaling that observer B has turned on their lantern. The experiment can now start.

* * *

**Galileo's Experiment**

* * *

"Okay hey, they're ready," Mio says, standing up.

"Ooh, lantern, lantern," Yukko says, carefully picking it up.

"Okay, just a sec, lemme make sure everything's ready," says Mio. She picks up the timer and her notebook and pencil. After shifting the items back and forth between either hand, she settles on holding the stopwatch in her right hand and the notebook and pencil in her left hand. "Okay, go," says Mio.

Yukko flicks the switch on the lantern, closing the shutter, drowning the two of them in darkness. This hill here is pretty far away from civilization, so there's no light pollution or anything. In the distance, after a short pause, that light disappears as well.

"Okay, how should we do this?" Mio says aloud. "How about at the count of three?"

"Mm," Yukko says.

"Ready…" Mio starts.

"Ready…" says Yukko.

They count together. "One… two… _three_."

The moment the third number is said, Yukko flicks open the shutter and Mio starts the timer.

00:00.08

—and Yukko spots the distant light blinking on, prompting her to immediately close her shutter. Upon this happening, Mio immediately stops the timer.

"Uh," says Mio.

"That was fast," Yukko says.

"As expected," Mio reminds. "Uh, can I get some light here?"

Yukko flicks open the shutter and points it Mio's way.

"Ack, not right in my eye," Mio says, holding up her arms. "Lower! Lower! Okay hm… let's see…" Mio looks down at the stopwatch.

00:00.36

"Point three six seconds," Mio says, copying the numbers into the notebook. "I think the start may have been a little off synch. Let's try that again."

Yukko nods, closing the shutter as Mio resets the stopwatch. The light in the distance blinks off.

"Let's count downwards this time," Mio suggests.

"Sure," Yukko says.

"Three," Mio starts.

The three of them continue the countdown together. "Two, one, zero."

Flick.

00:00.07

—distance blinks on, and then Yukko shuts the shutter and Mio stops timing.

"How was that?" Yukko asks.

"Sure, a little better, I think," Mio says, nodding. "Lights?"

Yukko opens the shutter and points the lantern at the stopwatch.

00:00.29

"Y'know, do we really need to turn off our lantern here?" Mio asks while writing down the number.

"Huh?" Yukko says.

"I mean, after we turn on our lantern, the only other thing we need to do in that particular trial is stop the timer," Mio says. "Yeah, now that I think about it, turning off our light is unnecessary."

"True, true," Yukko says, nodding. She closes the shutter on their lantern. Darkness.

The light in the distance blinks off.

"Three, two, one, _press_."

00:00.07

—blinks on, and Mio stops timing.

"Well, how was it?" Yukko asks, turning to Mio.

"Mm," Mio nods. "Point two four seconds." She carefully writes this into her notebook.

"It's getting faster," Yukko grins.

"No, it's just their reaction time," Mio says, looking off into the distance. The smallish point of light there blinks off. "They must be getting the hang of this experiment, and they're reacting quicker."

"Mm, mm," Yukko nods. "How fast is light actually, anyway? I know it's like really fast. I've called long-distance to someone on the other side of the world before, and the lag wasn't too noticeable."

"It's around three hundred thousand kilometers per second," Mio says. "Somewhere around there."

Yukko grins, holding up a finger. "So, one could say that in this experiment, the speed of light is negligible—"

"Though technically, we're not supposed to know that yet," Mio says.

"Huh?" Yukko says, tilting her head. "What do you mean? It's like the common era now!"

"Common era started 2011 years ago," Mio says.

"I mean like the modern era," Yukko says.

"Mm." Mio nods. "Still, we should get into the spirit of the Galileo time period. We're performing this experiment without presumptions."

"Electrical lamp," Yukko points to the lantern.

"Close enough, same difference," Mio says, shrugging.

"You mean 'feh'," Yukko says.

"Ah, don't worry, Yukko," Mio smiles. "The intent here is to gradually work our way up, ramping up accuracy exponentially as we move on in school. I mean, we know from the class lesson that the knowledge and technology in the 1600s was unable to do an observation of something as fast as the speed of light."

"For that really accurate number for the speed of light… When was that _getted_, anyway?" Yukko asks.

"That's not a word," says Mio. "And I don't remember. Relatively recently, I think."

"Sure," Yukko says.

In the distance, the light begins blinking on and off rapidly.

"Ack, they must be annoyed that we're taking too long," Mio says, reaching over and flicking shut the shutter.

Then, the distant light blinks off as well.

"Okay, let's try it again!" Yukko says enthusiastically.

The numbers that they get for the next three trials are:

1. 00:00.22

2. 00:00.16

3. 00:00.18

"I still don't think we're syncing it properly," Yukko complains. "You're probably starting the timer too late. The times that we're getting here are way too short."

"This is authentic," Mio smiles, writing down the latest result. "Back then, they didn't have electronic stopwatches or anything like that. Inaccuracy is to be expected. I think they had like this container of water that had a tiny hole in the middle so that the water would very slowly drip into the bottom part. Elapsed time was taken by counting the drops. Yeah, a drop timer. Water clock. One of those names."

"What?" Yukko says incredulously. "You sure? That can't be very accurate—"

"Like an hourglass in some respects," Mio mutters to herself.

"Well, we're in the modern age now," Yukko huffs. "Hm. Well, I know exactly when I'm going to turn on the light, so I should be the one to control the timer and stuff."

"That does make logical sense, I suppose," Mio says smiling, handing the stopwatch over to Yukko.

"Okay, how does this thing work?" Yukko asks.

"Ehh," Mio says. "You've never used a stopwatch before?"

"Well sure!" Yukko retorts. "A long time ago! I think. Maybe. But I've forgotten. Sort of."

"There's two buttons," Mio points.

"I realize that," Yukko says huffily.

"All right, that one," Mio starts, lifting her finger to point.

"Wait, just a sec," Yukko awkwardly juggles the lantern and stopwatch between her arms. The lantern's handle is quite distant from the shutter switch. "Um, how can I time it if...? Well maybe…"

"Can't you just flick the shutter switch there with your holding hand?" Mio asks, pointing to Yukko's left hand.

"I might drop it like that," Yukko protests. "It's sort of too… well…"

"How about I—" Mio suggests.

"Mm," Yukko nods, handing the lantern over to Mio.

"Okay, I think this might work," Mio says. She holds the lantern with both arms. "So, just make sure you flick the shutter at the same time as the stop—"

"Right, okay," Yukko says. "Stopwatch. Um, what's this button do?"

"As I was saying," says Mio. "Right. That right one starts and stops the timer. If you push the left one while the timer is stopped, it resets the timer."

"Right," Yukko nods.

"And if you push the left one while the timer is still going, it pauses the display without stopping the timer."

"Right, I see." Yukko starts the timer.

00:00.68

00:01.21

"Wait, really?" Yukko grins, looking down at the timer.

00:02.73

00:03.23

00:03.80

00:04.28

00:04.72

00:05.18

Yukko presses the left button.

00:05.35

"And the horses reach the quarter point at Oh-five-thirty-_five_!" Yukko announces with exaggerated emphasis.

00:05.35

00:05.35

00:05.35

Yukko presses the left button again, and the timer immediately jumps from five seconds to eleven seconds.

00:11.85

00:12.44

00:12.99

00:13.52

00:13.95

"Whoa, awesome!" Yukko grins.

"You're the only person I know that can get so excited about a simple stopwatch," Mio says in an amused tone.

"Well, it's the year 1600, right?" Yukko starts.

"Hm… Well no—" says Mio.

"So, this… precise timing technology is simply _amazing_!" Yukko gushes. "It's like the work of black wizardry! Witchcraft! You'd probably get burnt at the stake if you were ever found with one of these!"

"Actually, the Salem witch trials happened in 1692," Mio says.

"This could probably go for a lot of money back then," Yukko says.

"Hm… though that's not to say lots of scientists were unfairly executed for having differing worldviews," Mio says, trailing off, putting her fingers on her chin.

"Heh, heh," Yukko smiles as she hits the right button and then the left button.

00:00.00

"And again, I don't exactly remember the year of this experiment… And Nakamura-sensei said that she cared more about the understanding of the concepts rather than the dates…" Mio trails off. "No matter! Back on topic!"

"All right," Yukko says as she leans down and flicks a switch on the lantern in Mio's arms, closing the shutters. The light in the distance had turned off a long time ago.

With the stopwatch in her left hand and the switch in her right, Yukko waits for a few seconds. Then, she flicks the shutter switch while simultaneously pressing the stopwatch button. The timer starts. The distant light blinks on. She presses the button again.

00:00.17

"Damn, that was fast," Yukko says.

They do it again.

00:00.14

And again.

00:00.16

And again.

00:00.13

And again.

00:00.19

And again.

00:00.14

Again.

00:00.16

Again.

00:00.15

Again.

00:00.17

Again.

00:00.18

Again.

00:00.15

"Okay, I don't believe this," Yukko bristles. "There's no way that Mai-chan can be reacting so quickly. I'm like barely reacting in time to stop the timer as it is."

"Do you think she may be false-starting?" Mio asks.

"Hmmmmmmmmm," Yukko says suspiciously.

"Uh… Okay," Mio says, coming up with an idea. "If you want to make sure that this isn't happening, maybe wait for a random amount of time before turning on the light. Maybe first wait really long, and then really short, and then medium, and then really long again, or something like that. That way, there's no way that she'll be able to foretell when the light'll turn on. If she's false-starting, we can catch her that way."

"Ah, good idea," Yukko says, closing the shutters.

She waits for 35 seconds.

Flick, there's the blink, and then she stops timing.

00:00.18

Again. This time Yukko doesn't even wait 1 second after closing the shutters.

Flick, blink, and stop timing.

00:00.17

Again. Yukko waits 13 seconds.

Flick, blink, stop timing.

00:00.15

Again. Yukko waits 13 seconds.

Flick, blink, stop timing.

00:00.16

Again. She waits 5 seconds.

Flick, blink, stop.

00:00.14

Again. She waits 42 seconds.

Flick, blink, stop.

00:00.15

She waits 6 seconds.

Flick blink stop.

00:00.17

She waits 3 seconds.

Flick blink stop.

00:00.18

She waits 5 seconds.

00:00.15

She waits 7 seconds.

00:00.16

She waits 8 seconds.

00:00.14

She waits 4 seconds.

00:00.16

She waits 85 seconds.

00:00.18

She waits 69 seconds.

00:00.17

She waits 42 seconds.

00:00.15

She waits 13 seconds.

00:00.13

She waits 4 seconds.

00:00.16

"GAHHH!" Yukko shouts in frustration. "I can't believe this! There's no way that girl's reflexes are this good!"

Mio just watches in amusement.

Yukko waits 2 seconds.

00:00.16

She waits 3 seconds.

00:00.14

Waits 1 second.

00:00.16

Waits 1 second.

00:00.15

Waits 1 second.

00:00.14

Waits 1 second.

00:00.15

Waits 1 second.

00:00.12

Waits 1 second.

00:00.13

Waits 1 second.

00:00.11

Waits 1 second.

00:00.12

Waits 1 second.

00:00.11

Waits 1 second.

00:00.10

Waits 2 seconds.

00:00.13

Waits 2 seconds.

00:00.12

"I DON'T BELIEVE THIS!" Yukko shouts, flailing her arms in the air. "She's actually getting faster!"

"Well, by this point, her brain's probably all warmed up by now," Mio says.

"AGGH!" Yukko cries. She sighs.

"What were those last three numbers?" Mio asks, readying a pencil.

"Uh, right…" Yukko says. "Recording. Uh. I think they were 10, 13, and 12."

"Mm, that's what I remember too," Mio nods, quickly jotting down these numbers into the notebook.

Yukko is actually panting for breath a bit.

Mio blinks. "Wait, who's at the lantern, anyway?" She points at the mountain in the distance. "Is it Mai-chan or Nano-chan?"

Yukko blinks. "Ah…" She flushes. "Actually, to be honest, I just assumed it was Mai-chan."

"So competitive, you two," Mio deadpans.

"Twenty-three juices," Yukko sheds a tear. She immediately regains her composure, standing up straight. "Though if it's Nano-chan, then at least I understand. It's a given that a robot would have superb reaction times!"

"Eh, you're still on about that?" Mio sighs.

The light in the distance begins blinking on and off again. However, this repeated blinking is going on for a lot longer, now. It's showing no signs of stopping.

"Huh?" Yukko's eyes narrow.

"Huh?" Mio focuses on the blinking light as well.

The blinking is actually not random. Sometimes, the light remains on for a comparatively long period of time, and sometimes it's on for a relatively short period of time.

—flash dark flash dark flash dark flash darrrrrk flash darrrrrk flaaaash dark flash darrrrrk flaaaash dark flash dark flaaaash darrrrrk flaaaash dark flaaaash dark flaaaash darrrrrk flash dark flash dark flaaaash—

The blinking is pretty quick. This entire sequence passes in less than 5 seconds.

"Is that… Morse code?" Mio says, squinting.

Mio and Yukko turn to each other. "Definitely Mai-chan," they say in unison.

"Whaddya think she's trying to say?" Yukko asks.

"Saa," Mio shrugs her shoulders.

"You don't know Morse code?" Yukko asks.

"Nope," Mio replies.

"Huh…" says Yukko.

"Huh…"

A few seconds pass in silence as the blinking continues at a rapid pace. Mai's pace.

"Do you think they want to switch roles?" Mio asks.

"…" Yukko thinks for a moment. "What time is it, Mio-chan?" she asks.

Mio takes out her cell phone and turns on the display.

"Ah, what ever happened to 1600s?" Yukko says in a reprimanding tone, smiling.

"We _have_ been at this for almost 30 minutes," Mio says. "It makes sense that they'd want to be the A now."

"Aha!" Yukko grins evilly, rubbing her hands. "I'll show her! That Mai-chan! I'll beat all of her times! All of her high-scores!"

"Oi, this isn't a competition," Mio says light-heartedly. "Hm… how can we signal to them that we understand?"

"Let's just flicker it a lot," Yukko says, grabbing the switch and then flipping it up and down, up and down in quick succession. At least 4 times.

"Okay, I think that's enough," Mio says, gently pushing Yukko's arm away. "They've stopped transmitting the Morse code, anyway," Mio points out. It's true. The entire mountain is now dark.

"Okay, we're B now, right?" Yukko asks.

"Right, so we don't need to time the trials any more," Mio says, nodding to the stopwatch in Yukko's hands.

"So, what did B have to do again?" Yukko asks.

"Geez, forgotten already, have you?" Mio sighs.

"Yuppers!" says Yukko, grinning widely.

"Just… As soon as you see their light turn on, you turn on your light."

"Heh. Now, prepare to meet your maker, Mai-chan~" Yukko chuckles evilly.

" 'Meet your maker'?" Mio mutters to herself. "What does that even mean, anyway?

The light in the distance blinks on and Yukko reacts immediately, flicking on her lantern as well.

"How was that?" Yukko babbles. "I think that was good. Yeah, I think that was good. Heh."

"When is it going to be my turn?" Mio asks in an innocent tone.

"Yeah, yeah, yeah," Yukko waves her arm dismissively. "Just a minute. I need to beat her high score."

The lights both turn off, and they reset for the next trial.

The distant light turns on again, but Yukko is slower to react.

"Damn!" Yukko shouts. "She's a crafty one, that Mai-chan. But I won't be fooled!" She grins.

"My turn yet?" Mio asks in a disinterested tone.

"Mm, mm," Yukko waves her hand.

Darkness.

When the distant light turns on again, Yukko reacts with violent force and literally slams her fist into the lantern, sending it clattering to the ground.

"Oi, careful, careful!" Mio shouts.

"Don't worry, I've got it under control," Yukko says, bending down, sweeping her hands around to try and find the lantern in the darkness.

She finds it, and lifts it up again. She gives the shutter a quick flick to make sure that the lantern still works. Luckily, the light bulb isn't broken.

"You've cracked the glass," Mio comments, pointing at the lantern.

"Shh, shh. I need my concentration." Yukko slowly shifts into a ready stance. Her eyes narrow. Her eyes are trained on the distant mountain, waiting for the light to flicker on—

"Crap, I blinked!" Yukko cries, fumbling to open the shutter in time. "Ugh… You won't get so lucky next time, Mai-chan~"

"Oi," Mio says, raising a hand. "My turn?..."

Blink, flick.

"Aha! What do you say to that!" Yukko is gloating in the direction of the mountain. "Not too shabby, eh?"

"Uh…" Mio sweat-drops.

Blink, flick.

"That was also a good one!" Yukko grins.

"Uh… Yukko…" Mio's hand hovers hesitantly. Mio seems unsure of her actions.

Blink, flick.

"Oho, doing a long sequence of short waits, are we, Mai-chan?" Yukko grins.

Blink, flick.

"Trying to lull me into a false sense of security, are we?"

Blink, flick.

"Lulling me into a… hm, what's the word…"

Blink, flick.

"Aha! Lulling me into a state of complacency, are we?"

Blink, flick.

"Well, that's not going to work. Heh."

Blink, flick.

"Heh, heh, heh…"

Blink, flick.

"Ha, ha, ha!"

Blink, flick.

"AHA HA HAH HA HA!"

Blink, flick.

Mio watches with a bemused expression as Yukko breaks into maniacal laughter.

Blink, flick.

"Those two," Mio sighs, shaking her head. "Once Yukko gets into a competition with her like this, she just starts going nuts."

"Ho…" Yukko stops laughing, but the wide smile is still on her face. This time, the distant light is taking a lot longer to turn on. Yukko waits in the darkness with her senses hyper-alert.

"Maybe I could use this time to study for the quiz," Mio wonders aloud.

Blink, flick.

"AHA!" Yukko exclaims. "Still got it!"

"Mm, that's a good idea," Mio nods.

Blink, flick.

Blink, flick.

Blink, flick.

"I just need to make sure that all of the events are in my long term memory," Mio says aloud.

Flick.

"Sh… damn!" Yukko swears. She closes her shutter. "I'll need to make up for this false start by getting an extra-good time. Beating the socks off of Mai-chan. Heh." Yukko licks her lips.

Blink flick.

"I can use the moments of darkness to consolidate the facts in my memory," Mio says aloud.

Blink flick.

"…while using the temporary moments of light to check the facts to make sure I remember correctly," Mio nods.

Blink flick.

"How do you like them apples?" Yukko grins, pointing at the mountain triumphantly.

"Mm." Mio nods. "I have my notebook here, so that's convenient."

Blink flick.

"Victor!" Yukko smiles.

"Hm…" Mio says aloud. "So, in class, after Galileo, we started talking about a guy called Tycho Brahe…"

Blink flick.

"Ious!" Yukko grins.

Blink flick.

Blink flick.

Flick.

"くそ," Yukko swears. "Clever Pete!"

Blink, flick.

"It was around 1572," Mio reads aloud. "Brahe was an exceptional visual observer. Meticulous dude. He could discern detail to an accuracy of 1/60°."

Blink flick.

"Clever Philip!" Yukko shouts.

Blink flick.

"Also known as 1 arcmin," Mio says. "This is especially impressive considering the fact that these were pre-telescope times. He used a quadrant. Oh, and then there was like a diagram of how a quadrant worked. Mm. From the Uraniborg observatory that he built, he measured planetary positions, such as that of Mars."

Blick flick.

"Clever Felipe!" Yukko shouts.

"Especially Mars, in fact," Mio says. "He focused on it. Mm, mm… and Mars had an particularly eccentric orbit."

Blink flick.

"Clever Phyllis!" Yukko shouts.

"And there's like a diagram here," says Mio. "There's this weird complicated thing called retrograde loops."

Blink, flick.

"Clever plankton!"

"Also, an orbit diagram. Ah, so this retrograde loop thing would be the path that Mars would _appear_ take as observed from Earth."

Blink, flick.

"Clever zooplankton!"

"The precessing, rotating, and revolving Earth. Oh yeah… Back then, they still thought that everything revolved around the Earth."

Blink, flick.

"Clever anchovy!"

"Hm… Oh, also, did they still think the world was flat?"

Blink, flick.

"Clever tuna!"

"Ah, no matter, I'll get back to that later. So, let's see… Next, Brahe acquired an apprentice named Johan Kepler. He—"

Blink, flick.

"Clever bus!"

"—was a German mathematician, and also, he was ill a lot. Hm. I don't—"

Blink, flick.

"Clever boat!"

"—know what that's doing here. Seems a little off topic. Oh well."

Blink, flick.

"Clever human!"

"Kepler was to assist Brahe with the calculations, but Brahe died in 1601, leaving his academic inheritance to Kepler."

Blink, flick.

"Clever… stlaaaaaw!"

"Kepler was attempting to compute the shape of Mars' orbit. Understandably, this was difficult because as viewed from Earth, Mars was doing that weirded-up retrograde—"

Blink, flick.

"Clever blink!"

"—loop thing, which is pretty difficult to model mathematically. Hm. Uh…"

Blink, flick.

"Clever angel!"

"What's an equatorial measure, anyway? Mental note: Google it later. Uh…" Mio flips a page. "Right, Kepler's three laws. These are important. I'd better make sure I remember them. Memorize them."

Blink, flick.

"Clever—"

Blink, flick.

"Clever submarine!"

"One. All orbits are ellipses. But 'ellipses' is crossed out and above it says 'conic sections'. Huh. Well, a parabola is a conic section, right? Hm… I suppose this makes sense…"

Blink, flick.

"Clever osteoporosis!"

"Two. Equal areas in equal times. And here's a diagram of an ellipse with some pie-like wedges. 'If and only if A1 equals A2 double arrow T1 equals T2'."

Blink, flick.

"Clever Diefenbunker!"

"Three. Uh?... Period squared backwards fish symbol semi-major axis cubed. Wait, that backwards fish symbol… I know this. I know this. Uh… what was it again?"

Blink, flick.

"Clever aether!"

"Uh… Hm… I'm pretty sure I've seen it in math before, too."

Blink, flick.

"Clever cataract!"

"Proportional to! Yes, of course! Right. So, the square of the period is directly proportional to the cube of the semi-major axis. That's the third law. Mm."

A few seconds pass in silence.

Blink, flick.

"Antidisestablishmentarianism !" Yukko cries.

"Let's see here," Mio mutters, skimming over her notes. "Shaping optics… Asylums were like reality television… Pope skipping 10 days in October in 1642…"

Blink, flick.

"Pneumonoultramicroscopicsili covolcanokoniosis!" Yukko shouts.

"Yukko, is that even a word?" Mio asks skeptically, eyebrows furrowing.

"It is," Yukko grins. "It actually is!"

"Huh…" Mio is not convinced.

Yukko closes the shutter, waiting to begin yet another trial.

"Is it my turn?" Mio asks. "I've been waiting patiently all this time…"

"No, I'm still not satisfied!" Yukko says, holding up a hand. "None of my reaction times have really stood out yet. I want to break 100 milliseconds!"

"Yukko, that's impossible," Mio says, rolling her eyes.

"Mm, just a little longer!" Yukko doesn't look away from the mountain.

"Yukko," Mio says.

"Quiet. I need the utmost concentration. No distractions." Yukko has a serious look on her face.

"Ugh," Mio rolls her eyes again.

_We ended up continuing this experiment well into the night_, Mio narrates.

_We swapped roles as A and B several times after that. I actually did get to try out the lantern and timer after all. For like 15 minutes. While Yukko got hours to herself. I can't believe those two. So competitive. _

_Still, by the time Yukko wound down enough to be willing to give me a shot, I was ready to crawl into bed. I got up pretty early that day, after all. And I still can't read Morse code, but I'm pretty sure that at that point, Mai-chan and Nano-chan wanted to go to sleep, too. The cold really tires you out, doesn't it. We were fast asleep by 11 pm. Wait, did we seriously just spend 5 hours just flashing lights at each other? Seriously? Agh! I used up all that time... I still have so much school work to do! There's that project and that history test and history presentation and English reading!... Bleh! Ack!... Gah... _

_In any case, based on our numbers alone, we concluded that, similar to what Galileo concluded, the difference in time was too small to be detected with this equipment. Therefore, we decided that light was "fast". _

_Much faster than 10 km/s. Perhaps 1000 km/s or more. Ah, don't worry about the exact number. Nakamura-sensei says that we'll get to that later. Okay. Good._

_Yukko isn't that good with numbers, so she gave all of our recordings to Mai-chan for her to number-crunch. They decided that they were going to look at their final score results tomorrow at lunch. Mai-chan was going to isolate the numbers obtained by herself and Yukko, ignoring the numbers obtained by Nano-chan and me. Don't ask me how she's going to do that. And also, they somehow have a bet set up about this, even though we had no method of communication between each other back there on the hills. Feh._

* * *

日常 - nichijou, Arawi Keiichi


	2. Mai and Nano

A/N: Warning: Lots of irrelevant exposition.

* * *

日常 - nichijou, Arawi Keiichi

* * *

"—realized that when a cannon was fired from a distance, the sound followed the light by a number of seconds," Mai is saying.

Nano is listening attentively as they hike up the mountain path.

"At that time," Mai continues with an expressionless face, "they knew that the velocity of sound was approximately 333 meters per second."

"Mm," Nano nods with a serious look on her face.

"In 1638, through the use of lanterns with shutters that could rapidly open and close…"

"You mean like the ones that we have?" Nano holds up the electric lamp in her hand.

Mai nods, still expressionless. "…in combination with a drop timer, Galileo devised an experiment to obtain an initial estimate for the speed of light. After the experiment, he concluded that the difference in time was too small to be detected with their experiment, and that the speed of light must—"

"Wait!" Nano says nervously, holding up a hand.

Mai regards Nano impassively.

"Uh… should we really spoil the outcome of this experiment before we actually do it?" Nano asks.

"Don't worry," Mai says. "There are no spoilers."

"But wouldn't knowing the results spoil the fun?... Er…" Nano smiles nervously.

Mai shakes her head. "There _are_ no spoilers."

"Um… but…"

Mai stops and stares into Nano's face with slightly raised eyebrows. "THERE ARE NO SPOILERS."

"…" Nano is speechless.

Then, Mai turns around and continues walking.

_I wonder if I angered her?_ Nano wonders.

Mai continues speaking with no change in tone. "Though it's true that knowing the outcome may bias the experiment, the speed of light is common knowledge, as is the result of this primitive experiment." Mai turns her head towards Nano, not slowing her pace.

"Uh… okay?..." Nano says confusedly.

Mai nods. "The next notable attempt at measuring c occurred in around 1675, by Ole Römer. He was convinced that Galileo had shown that c was extremely quick, so he devised an astronomical method to measure c. He made predictions of phenomena centered around Jupiter. Specifically, the timings of Io eclipses."

"Uh?..." Nano makes a confused sound.

"Eclipses were quite easy to observe at the time, given their primitive telescope technology. Occultations were easy to spot. However, transits and shadow transits were more difficult to observe—."

"Wait, what do those four things mean?" Nano raises a finger.

"Rømer noticed discrepancies in the timing of the eclipses at different times in the year."

"Um?..." Nano closes her eyes, smiling nervously.

"When Earth was closer to Jupiter, the eclipse would occur early. When Earth was further away, the eclipse would occur late. These discrepancies were attributed to a finite speed of light."

"But… Er…" Nano isn't sure what to say.

"These timings were used in combination with the AU value to produce a value of c with the distance speed time formula."

"AU?" Nano isn't following.

Well, she's physically following Mai on the path, but she isn't following.

"The value of c was determined to be approximately 230,000 kilometers per second. This inaccuracy was due to an incorrect valued for the AU. In any case, the scientific world deemed this speed to be unreasonable and thus ignored it."

"Ignored it?" Nano says, still smiling nervously. Speaking of ignoring… "Ano, Minakami-san?"

"After Roemer's attempt to measure the speed of light. Other scientists followed this attempt in the following order: Bradley, Fizeau, Foucault," —almost imperceptible pause here— "Michelson…"

"Minakami-san?" Nano interjects in a slightly more assertive tone.

Mai stops walking and turns around to face Nano. She stares at Nano for a few seconds.

"Um…" Nano says. "I don't understand, but… why are you talking all of a sudden?"

Mai blinks.

"Ack! Not that that's a bad thing or anything," Nano frantically waves her hands. "And what you're saying sounds sort of interesting, I think, but there's so many names and…" She trails off.

Mai blinks again.

Nano takes a step backwards. "Um… Minakami-san?"

"You entered our class late in our school year," Mai says.

"Doki!" Nano takes another step backwards. _It's true… That isn't the sort of thing normal people would do… Is she on to me? Is she… suspicious?_

Mai raises an eyebrow. "Our destination is that way," she says, pointing forwards along the path.

"Um…" Nano looks around nervously. "Ah, there's a perfectly good reason for that! Uh, you see…"

"You're not a very good liar," Mai comments.

"Eek!" Nano sweats. "Um… I'm not… er…"

"We need to be at our destination by around sunset."

Nano continues to stammer.

"It's my understanding that we have a physics test coming up," Mai says.

"Oh…" Nano sighs in relief. "Is that what it was? Nothing I did or said?"

Mai blinks. "Reviewing these topics out loud reinforces my memories."

"Oh, I see." Nano nods.

"Rewriting these facts does even more for memory reinforcement, but obviously, that's not viable now," Mai says.

"Ah…" Nano scratches the back of her head, smiling nervously. "But still, all of this talking all of a sudden… it's sort of… weird, you know, Minakami-san?"

"What's more concerning is how little you understand these things," Mai says.

"Huh?" Nano asks.

"The test is in four days," Mai says.

"Mm?" Nano tilts her head.

Mai holds up four fingers.

Nano also holds up four fingers. "Four…"

Mai nods.

Nano sweats. "Well, we're doing this experiment today, so I guess I'll start reviewing my notes tomorrow…"

"It takes more than one day to study for a test of this magnitude," says Mai.

"Uhh…" Nano says.

"In any case, we're falling behind. Come." Mai turns and continues walking down the path. Nano follows.

A minute passes.

"It's very interesting," Nano says, trying to make conversation. "You usually never talk, and here you are, talking!"

Mai continues walking.

"Maybe I should tell Aioi-san and Naganohara-san," Nano smiling. "Do all people change their behaviour like this before a test?"

"Studying is important," Mai says. Her eyes narrow slightly.

"I see…"

Mai's eyes narrow even more.

* * *

"Here are your tests back," said the teacher. "Let's see here… hand this one back to Nakanojou. Hand this one back to Naganohara. Hand this…"

The teacher went through the pile of papers in his hand one by one, giving them to students sitting in the front row of the classroom. These students then passed the test papers from desk to desk, returning each test to their respective owners.

At this point, students started playing the "what did you get" game. The teacher wasn't even done handing out the tests yet.

"Ooh, an 85!" Yukko said, leaning forward and looking over Mio's shoulder.

"No, it's not a very good score," Mio said, brushing Yukko off. "I can do better."

"I have a good feeling about this test," Yukko said, grinning. "I bet I could even beat your score!"

"You could not," Mio said in a light-hearted manner.

"Do you remember my legendary day?" Yukko asked. "That was the day I got an 80! I feel that I can recreate that day! I can feel it…"

"Pass this to Aioi." The student sitting in front of Mio turned around and passed a test to Mio.

"Speaking of which, here it comes now!" Yukko said excitedly.

Mai was reaching forward and taking her own test from the student sitting in front of her.

"Aww, it was a 68!" Yukko exclaimed loudly for the entire class to hear. There were some light chuckles here and there.

Mai stared at the red number circled on the front of her own test paper.

61.

With her test still in her hands, Mai leaned forward and let her head fall on the desk with a soft _clunk_.

The "what did you get" game continued in the background as the teacher handed out the last of the tests. Yukko was still conversing loudly with Mio in the background as Mai sat there with her head on her desk.

Then, Mai jerked upright in her seat with a determined expression. Metaphorical flames flared in her eyes.

_It won't be like this next time!_ Mai clenched a fist. _Yaruki… hyaku-nijū pāsento!_

* * *

_やる気__...120__パーセント__…_

The memory echoes in Mai's mind. She nods. Motivation. Her face is expressionless.

"Please ask me questions concerning the science test," Mai says, turning to Nano. "It would benefit us both."

"Ah… really?" Nano smiles widely. "Thanks!"

Mai waves it off. She remains impassive.

"So… um…" Nano looks up in thought. "Where to start?..."

"There are many topics that may be on the test," Mai says. "There are the various experiments to determine the speed of light. Also, orbits. Quantum effects. Light's wave-particle duality. The aether. Black-bodies. Atoms. Matter waves. Relativity. Quantum tunnelling. The uncertainty principle."

Nano's expression blanks out. "None of those terms are familiar to me."

Mai blinks.

Nano stares at the back of Mai's head.

Mai blinks.

"Um." Nano grabs the straps of her own backpack.

"Pick one unfamiliar term," says Mai.

Nano's expression blanks out again. "Actually, I don't really remember any of what you just said."

Mai blinks.

Nano stares at the back of Mai's head.

They continue walking down the path.

Mai's eyes flicker around. Abruptly, she stops walking. Nano almost runs into Mai.

"Huh?" Nano asks.

Mai takes a look at the sky. The sun is pretty low in the sky. "This way," she says. She walks off of the asphalt path and up the steep rocky earth off the side of the path.

"Sh…shouldn't we follow the path?" Nano points nervously to the path.

"No need." Mai's face is expressionless.

"Um…" Nano runs and stumbles, catching up to Mai.

"So, what is light, exactly?" Nano asks. "I know we're going to use lanterns to try and measure the speed of light here, but what is it?"

"Visible light is just a portion of the entire electromagnetic spectrum."

"Electro- wha? Augh!" Nano stumbles and almost falls over. Mai grabs Nano's wrist and regains her balance.

Mai blinks. She takes off her backpack and pulls out a rope.

"Eh?" Nano stares at the rope. "What's that for? And really, it's sorta steep here… I think we should return to the path…"

"No need," Mai says, tying one end of the rope around her own waist, and then reaching over and typing the other end around Nano's waist.

"Um, what's this for?" Nano tugs on the knot a bit. Mai tied it very tightly.

"In case you fall off a cliff." Deadpan.

"Ehh!?" Nano is suddenly very nervous.

Mai throws on her backpack again and continues walking. The rope is fairly long. When the rope is stretched taut, they're nowhere within arm's reach of each other.

Nano stands, looking around nervously as Mai walks on ahead. But the rope is quickly getting tauter, so Nano pushes herself forward and continues walking up the hill.

"This hill isn't very steep," Mai says. "The slope is only approximately one."

"Slope?" Nano looks confused.

Mai continues walking. "…You'll need to learn about that, too. For the math quiz in two weeks."

"Eh…"

They walk in silence for a while.

"Wait, so electro what?" Nano asks again.

"Electromagnetic radiation," says Mai. "Visible light is one type. Radio waves are one type. Microwaves are one type. Gamma rays are one type. Infrared is one type. Ultraviolet is one type."

Nano's eyes

* * *

"—that robots can't get sunburn!" Hakase shouted in the heat of the moment.

"Wh…what?" Nano eyes got watery.

Hakase grimaced, stepping forward to comfort Nano. "Um… Nano? Well, if you really want to, I can modify it so that you can get sunburn… Nano?... Please don't—"

* * *

widen. "Oh, I think I've heard of ultraviolet before," Nano nods. "In fact, I'm wearing sunscreen right now to make sure that I don't get sunburned." _Like a normal girl_.

"The colour of light is dependent on the frequency or wavelength of light," Mai says.

Nano raises her hand. "Two questions. What is frequency, and what is wavelength?"

Mai takes a moment to gather her thoughts. "Frequency is how many times something happens in a unit time. Hertz is a common measurement. Wavelength is simply the distance between two crests of a wave."

Nano raises her hand. "Three questions. What exactly is a hertz? What is a crest? So why's light dependent on both wavelength and frequency? How's that work?"

Mai blinks. "Hertz is how many times the event occurs in one second. For example, if a light blinks once every second, it has a frequency of 1 hertz. If a light links 25 times every second, it has a frequency of 25 hertz."

"Ah," Nano says. She raises her hand. "Five questions—"

"Let me finish your previous three questions first," says Mai. "As for a crest… It is the point on a wave that's highest. You've been to the ocean before, right?"

"No."

Mai pauses. "Have you been to a lake, river, pond, fountain or any large body of water?"

Nano searches her memory. "I'm not sure."

"Do you know what a wave is?"

"…" Nano pauses, trying to find a good phrasing of her explanation.

Mai is looking sort of disturbed right now.

They approach a rock face. "A wave looks like this." Mai takes a chalk out of her pocket and draws a wave shape across a large flat piece of rock.

"Ohh," Nano says. "Oh yeah, I think I know what you're talking about."

Mai draws a horizontal line across two wave tops. "This is a wavelength."

"Oh, I see," Nano says, nodding.

Mai steps onto the rock face. "We're going up," she says as she begins the climb up the rocks.

"Uh… EHH?" Nano freaks out and takes a step back. "What? We don't have any sort of gear or protection or…"

"I am an experienced rock climber," Mai says.

"What about me!?" Nano yells, waving her arms back and forth. "I have no idea how to climb rocks!"

"Learn, then," Mai says. The rope has gone taut now. Mai tugs on the rope a bit to get Nano moving.

"But…" Nano says, sweating furiously.

"This rock face only has a slope of approximately four," Mai says. "No trouble."

"Ehh…" Nano tries to start climbing. After the first few steps, she loses her footing and plunges downwards. Mai continues climbing upwards, paying no attention to Nano's distress.

"Um…" Nano is being held by the rope, so she isn't falling back to the ground or anything. The rope is acting like a safety harness for her. Mai seems to be experiencing no trouble at all, despite Nano's added weight. Mai's climbing looks as effortless as walking.

"The wavelength is inversely proportional to the frequency," Mai says as she continues climbing. "If the wavelength increases, the frequency decreases. And vice-versa."

"Ah… hah?" Nano is struggling to climb up the rocks. There aren't any really substantial footholds anywhere.

"Moving on to James Bradley," Mai says. "He believed Romer's work to be sound, and thus made his own calculations of the speed of light."

"Hn?"

"When doing his measurements, he accounted for all of Earth's motions. This includes rotation, precession, revolution, and nutation. He was very meticulous."

"Wh… what? What are those four Earth's motions things?"

"Those aren't the main focus of the test."

"But..."

"Focus on the test. The test is in four days."

"Ok…okay?..."

"Because the speed of light was finite, there would be minute differences in the apparent locations of stars as Earth orbited the sun. If the apparent position was plotted over the course of the year, it would trace a circle in the sky about 20 arcseconds distant from the true location."

"Arcsecond?"

"One degree equals 60 arcminutes equals 3600 arcseconds."

"I'm not very good at math…"

"The key word here is 'stellar aberration.' "

"Um, what?"

"Google it. Stellar aberration was used to calculate an accurate estimate for the speed of light."

"What, how?"

Mai climbs to the top of the rock face and then turns around to reel in the rope as Nano slowly approaches. "The idea was that if the angle from the vertical is measured, you can infer the speed of the moving projectile. In this case, light."

"What? I don't understand… Example?..." Nano's hands emerge, grabbing onto the ground on the top.

Nano is breathing heavily. Mai pulls Nano up and puts her on relatively flat land again. As soon as her feet come in contact with the ground, she immediately scatters away from the edge.

"…" Mai pulls a water bottle out of her backpack. She unscrews the cap and starts holding it higher.

"Wait, what are you doing?" Nano is immediately on guard.

Mai pauses, blinking. "Rain," she says. She holds the water bottle even higher, starting to aim it towards Nano. A little water drips out.

"No, never mind, never mind," Nano says, rapidly waving her hands. "I can Google it later. No need for rain, no need for rain."

Mai puts the cap on the water bottle again and then puts it away. "Very well."

Nano breathes a sigh of relief.

Where they're standing right now is only a handful of paces away from another asphalt path. "Wait, is that?..." Nano points at the path, noticing it for the first time.

Mai begins walking forward onto the path. Nano follows before the rope can go taut. "Minakami-san…" she sighs, wiping some sweat off her brow. "Was that shortcut really necessary?"

"Bradley ended up obtaining a value of approximately 301,000 kilometers per second," Mai continues as if they had been walking normally this entire time. "However, the definitive value still required testing, and this was beyond the 1740s technology."

"So this was 1740?" Nano asks, trying to calm her breathing.

"The next person to measure the speed of light was Fizeau in 1849. Light was shone through a rapidly rotating teethed wheel. The light bounced off of a mirror kilometers away, and then came back through the same wheel. The wheel rotation speed was known. The mirror's distance was known. When the light was observed coming back through, the speed of light could be deduced. However, the value obtained was inaccurate because of diffraction. Around 305,000 kilometers per second."

"Okay…" Nano says.

"In 1850, another researcher, Foucault, replaced Fizeau's disc with a rotating mirror. He continually increased the accuracy of the apparatus until his final measurement in 1862."

"Oh, I see. They were getting more accurate as time went on." Nano nods.

Mai begins veering away from the path.

"Oh…" Nano sighs. "Minakami-san… Not again…"

They begin walking up a steep rocky slope, away from the path.

"Is this really safe?" Nano asks.

"No." Mai continues walking. "Don't try this at home."

"Don't try this at… ghhh…" Nano sighs. She begins sweating furiously.

Mai starts getting serious. She marches faster. Nano starts struggling to keep up. They're hiking up steep hills. Hills with little footholds. Hills with lots of rocks. Hills that easily give sprained ankles. They don't get any sprained ankles, though.

"In the 1870s, Albert Michelson began to consider definitive experiments on the speed of light and optimized the experiment set up by Foucault." Mai is talking very quickly.

Nano is too out of breath to say anything.

"He used custom lens. Precise distance measures. Obtained a value of c that would remain the most accurate for fifty years. 299,979.8 km/s."

Mai leads Nano up a vertical rocky cliff.

"Newton examined light's physical properties in his 1702 book "Opticks", in which he suggested light was corpuscular. Particulate."

Nano is basically just hanging on the rope as Mai pulls Nano up the cliff.

"In 1802, Thomas Young, known for his translation of the Rosetta Stone, was the one who performed the double-slit experiment. The resulting interference pattern was a strong indication that light was a wave."

Mai walks onto a shaky-looking rope bridge without hesitation.

"There was an essay contest to explain the interference pattern with corpuscular theory. People back then wanted to cling to corpuscular theory. Fresnel did the opposite and instead supported wave theory in his essay. He won the contest."

Nano clutches the rope handles with a death grip as she very slowly inches her way across the bridge. Three-quarters of the way, she drops down on her knees and crawls the rest of the way. Mai is still nonchalant.

"Poisson didn't believe in wave theory. He deduced from Fresnel's work that there would be a bright point in the shadow of a circular object being shone on by a point light source."

Nano runs up behind Mai and clutches the girl's shoulders, shivering. Mai pauses for a moment, taking note of this.

"This concept seemed ridiculous to the scientists of the time."

Mai walks on, and Nano stays right behind Mai, not letting go.

"Mr. Poisson set up an experiment to discredit Fresnel's work. The experiment ended up verifying Fresnel's work instead."

_Boom._

Mai walks up the slope and crosses the yet another asphalt path at a 90 degree angle. Completely bypassing it.

"The bright spot that appeared in the experiment became known as the Fresnel/Poisson bright spot. This was the deciding evidence that light was a wave."

The slope of the hill is 7.

"All waves must propagate through something, they said. What medium does light use? The planets aren't slowed down by drag from this material, whatever it was. Otherwise, they'd eventually spiral into the sun, and that's clearly not happening."

Mai double-crosses back on their path, going down again, and then she starts venturing out in a different direction onto a very small ledge.

"They created this medium that had no mass, no drag, and allowed light to propagate. They called it the luminiferous aether. Luckily, this æther was disproved soon enough."

A small chunk of rock that's knocked loose by Nano's foot goes clattering down the steep vertical rock until it hits the pond well over 700 meters below. Nano makes a terrified sound, gripping the rock as tightly as she can. Mai continues edging leftwards out onto the ledge, speaking in a nonchalant tone.

"In the 1860s, James Clerk Maxwell unified electricity and magnetism. He developed four equations which describe all electrical and magnetic phenomena. These equations are very fundamental in physics."

Mai reaches the other side and then immediately begins climbing up the vertical rock face. Nano isn't even off the ledge yet. She's still inching left at a very, very slow pace.

"Maxwell also used his vector calculus to derive to a value of c from electricity and magnetism. A crowning achievement. He was so excited that he had trouble sleeping for three nights." Mai turns a sharp gaze to Nano below. "You'd better sleep properly prior to the test."

"H-…hai, Minakami-san!" Nano says, trying to keep up with Mai.

Mai nods. She climbs up onto another narrow ledge and begins slowly stepping towards the right.

"There was something about the 3-D function that's related to sharp edge diffraction pattern somehow— I don't remember— If the function is viewed from the yz plane, it takes the shape of a Cornu spiral. Also known as an Euler spiral."

As Nano haltingly follows, Mai reaches the end of the ledge where the path widens.

"Cornu spirals are actually used in freeway off-ramps and various other places. Interesting, isn't it. But back on topic."

Mai walks down the path to a set of stairs. The stairs are so steep that it's more like a ladder than stairs.

"Topic?…" Nano breathes, putting all of her effort into not losing her foothold and tumbling downwards. "Tropics… Tropic of Capricorn… South… Australia… the Down Under… Down… Downstairs… Stairs… Really steep stairs… Really long steep stairs… Not falling down really long steep stairs… uh huh… Yes, Minakami-san."

Mai continues speaking. "And then Michelson and another person— I don't remember who— decided to invent a device so accurate in measurement that it could determine whether or not the aether existed."

Mai walks along the rocky path. Nano stumbles after Mai.

"Spoiler alert," Mai says. "This device proved that the ether does not exist."

"Minakami-sannnnn," Nano sighs.

"The diagram that we have in our notes is a simplified version. The actual version that Michelson used had the light bounce back and forth in several passes to increase the accuracy. This device, Michelson's interferometer, used half-silvered mirrors and light beams to create fringe patterns. These patterns can be used to measure distances accurate to plus or minus a few nanometers. I don't know… it's hard to explain the exact mechanics without a diagram."

"I'm sure you guys will show it to me in one of our last-minute study sessions," Nano pants.

They reach a rapidly flowing stream. Just a hundred meters downstream is a giant waterfall and hundreds of meters of drop.

"We really need to stop procrastinating so much," Mai says. "Those past-midnight sessions can't be too good for us."

"I guess…" Nano shrugs. She's trying to make the best of the short rest they're having here as Mai surveys the scene.

"In any case, if there was an æther, minute changes in the speed of light would've been detected because of the motions of the Earth. However, no such change was detected. Thus, they concluded that there was no aether."

Mai steadies her balance and actually begins walking across a log that's precariously laid across the length of the stream.

"So, that was that. What else was there?..." Mai ponders this nonchalantly as she crosses the stream. "Oh, there was a Hertz person who in 1886 produced the first man-made radio waves. Mn." Mai finishes crossing.

Nano hugs the log for dear life as she slowly crawls forward.

"We also had some notes about black-body radiation. Kirchhoff's first law: A hot opaque object, ideally a perfect black-body, radiates a continuous spectrum. The rate of this radiation is defined by a property called emissivity. The height and peak of the black-body curve depends on the object's temperature."

Mai ends up having to walk back and pull Nano into a piggyback to get her across the stream.

"Oh. By the way, there are two types of radiation. Ionizing and non-ionizing. Light is a type of radiation. Uranium-235 also releases radiation. Ionizing radiation. Ionizing radiation like that can be pretty harmful to humans, Nano." Mai gives Nano a lingering look as she puts the girl down on the ground.

Then, Mai stops, goes back a few steps, and gives the log a powerful kick. The log dislodges itself from the couple of rocks that were holding it in place. The log slowly turns around as it approaches the waterfall.

"Kirchhoff's second law... A thin hot gas emits light at only a few specific wavelengths. Emission lines. The rest of the spectrum is dark. For example, the emission spectrum of hydrogen is very simple and common."

It flies off the edge of the waterfall and falls, and falls, and falls…

"In fact, in around 1882, a person called Balmer came up with an equation to relate a spectra line of hydrogen to its wavelength. The Balmer series."

Twelve seconds later, a sickening crunch sounds. Nano gulps.

"And Kirchhoff's third law is like the reverse of the second law. Surrounding a hot object with a thin cooler gas results in an almost complete spectrum. However, the gas absorbs photons from the black-body radiation at a few specific wavelengths, resulting in an absorption spectrum."

At top of another cliff, Mai waits for Nano to finish climbing up.

"Light is absorbed by the gas at the exact same wavelengths as it would emit light from if it is hot. They're like the same thing. Something to do with electron jumps or something. I don't remember. Also, I think sensei said something about being able to see both the emission spectrum and absorption spectrum from the same object, only needing to change the angle from which you're looking at it. Emission or absorption, it only depends on what's behind it, supposedly."

Mai and Nano meet the asphalt path again.

"We can get absorption spectra from the sun and all sorts of stars. We're viewing the light from the sun after it goes through the chromosphere, so there would be absorption lines. From this we can deduce the chemical composition of the sun by matching absorption lines we observe to the absorption lines from various elements. We can also deduce the temperature of the surface of the sun by matching the black-body curve shape."

Mai turns onto the path.

"Uh… okay…" Nano sighs. "I think I'm going to need to have that explained to me several more times."

"Several," Mai says.

"Mm," Nano nods.

"Lecture 10: Introduction to Kirchhoff's Laws." Mai continues to lead Nano along the path.

"What?" Nano asks. "What is that?"

"50 bun oyobi 28 byou," says Mai.

"Hmm…" Nano closes her eyes, sighing. "Okay, what's next?"

"In around 1900, Max Planck, a physicist, created a hypothetical experiment oven… thing… something to do with black-bodies."

_Boom._

"Planck suggested that electromagnetic radiation is transferred in the oven in discrete quanta rather than a continuous wave form."

Mai takes out a pick and hammers it into the middle of the path. Then, she wraps a rope around the pick.

"He thought this only applied to his ovens, but it's actually one of the fundamental principles of quantum mechanics. Electromagnetic radiation is transferred in discrete packets of energy called photons. Eγ equals hfγ. Oh, I don't remember what h stands for, though. But f is frequency and E is energy."

Mai reels out the rope as she walks forward, staying true even as the asphalt path begins curving.

"You've heard of Albert Einstein before, right?" Mai asks.

"Yeah," Nano nods, nervously following Mai. "He's that guy, y'know?"

Mai pauses for a moment, turning to give Nano a look.

"You know," Nano says. "He did that thing. At that time. At that place. Because of that reason."

Mai pauses for a moment longer.

"He's a famous scientist," Nano smiling. "That's all I really remember. I'm… er… guessing he had something to do with… light?" Nano trails off as she watches Mai do something crazy again.

Using the rope and the pick as a safety-line, Mai leaps out and begins descending the cliff side, quickly letting out more rope as she descends, periodically rebounding off the cliff wall.

"Why haven't you ever used these safety lines before?" Nano sighs, trying to keep up with Mai. Nano is above Mai.

"The other cliffs were easy," explains Mai as she reaches the bottom.

After walking in one direction for a while, Mai begins climbing up another cliff. This time, the face at the top actually goes past the vertical in slope.

"It was Einstein who suggested that quantization was a true property of light, rather than being just a property limited to Planck's ovens or whatever. 1905. Also in 1905, he came up with special relativity. Pretty good year for him."

The top of the climb has them hanging upside down at a 45 degree angle.

"He suggested that c was the universal constant even between co-moving references. This was an incredible claim, and a pretty risky one too for established scientists, but Einstein was an outsider at the time, so…" Mai trails off as she climbs up onto solid ground again.

In the distance, a large tree has fallen over, blocking the way onto a bridge. This bridge isn't like that rope bridge that they went on earlier. This is an actual legit sturdy bridge, capable of supporting up to 15,000 lbs of weight. The asphalt path leads up to it. And they need to cross this bridge to get to their arranged meeting spot.

Mai looks to the west. The sun is already partly obscured by the horizon.

"The bridge is blocked," Mai says as Nano climbs up too.

"Oh no," Nano pants, scooting away from the edge and then taking a seat on the ground. "We're going to be late, even after all of those shortcuts?"

Mai's mouth twitches for a moment. "Yes, shortcuts," she says expressionlessly.

"What should we do then, Minakami-san?" Nano asks, still trying to catch her breath. "I don't want to let Naganohara-san and Aioi-san down."

"Hm," says Mai, surveying the scene. She walks up a bit closer to the chasm and peers down below. There's a calmly flowing stream about 100 meters below.

Nano stands up again. Her legs are a bit shaky. She walks up to Mai.

"Do you know how to walk a tightrope?" Mai asks casually, reaching into her backpack and beginning to pull out a rope.

Black and white. Nano freezes for a while.

Mai takes a sharp metal thing out of her backpack as well and begins tying it to the rope. Presumably, she's going to throw this thing to the other side so that the rope is anchored to something.

"Um… no…" Nano turns to the bridge again, just a little ways to the right. "Could we… I dunno… just climb over the log?"

Mai turns to the bridge. The top of the log is significantly higher than the railing of the bridge. "That works, too." Deadpan.

"Oh… thank you, Minakami-san," Nano sighs in relief.

Compared to their previous rock-climbs, getting over this 3 meter thick tree log is pretty easy. They get past the log and cross to the other side within 3 minutes.

"How much further is it from here, Minakami-san?" Nano asks.

Mai looks at the horizon. The sun has now completely set. There's just the orange red glow left over. "Perhaps 15, 20 minutes. However, we do still need to set up camp while there."

"Mm," Nano nods as Mai begins walking forwards again.

"Do you remember the procedure?" Mai asks.

"That much I remember," Nano nods.

"Do you want to be the first to operate the lamp?"

"Well… do you want to?"

"Do you want to?"

"Uh, do you want to?"

"Do you want to?"

"Er, do you want to?"

"Do you want to?"

"Um, do you want to?"

Mai takes something out of her backpack.

"Uh, what's that, Minakami-san?" Nano asks.

"It's not plastic explosives," Mai says.

"Ghhh…" Nano sweats.

Mai stops, gets into a ready stance, and hurls the little package away as forcefully as she can. The package flies off the edge and plummets out of sight.

Nano immediately plugs her ears and squints her eyes shut, turning away.

A few seconds pass in silence.

"I said, they aren't plastic explosives," Mai says. She begins walking forward again.

"Uh… oh…" Nano looks nervously in the direction that Mai threw the package. Nothing is exploding or anything from there. "Isn't that littering?"

"Fifty fifty," Mai says.

"What?"

"Nes yo."

"What?"

"…"

"…"

"I'll pick it up later," Mai finally says. Her expression is the same as always.

"Oh…" Nano says.

They continue walking in silence for a while.

_She must have tired herself out from all of that talking,_ Nano thinks, smiling. "So, Minakami-san..."

"Call me Mai," says Mai.

"Huh?" Nano's heart rate increases. A_ first-name basis!_ "Really? Is that… really okay?"

"Yes," says Mai. Her expression is unchanged.

"I'm glad," Nano smiles. _We're becoming closer friends…_

"It's more efficient," says Mai. "Less syllables."

"Eh?"

"If you keep calling me Minakami, then in the long run, lots of unnecessary time will have been wasted."

"O… oh," Nano says.

They continue walking for a while.

"When did Naganohara-san and Aioi-san start calling you by first name?" Nano asks.

"Yukko…" Mai says. "From the moment I introduced myself."

"Wow," Nano grins.

"She always does that," Mai says. "She tried calling the teacher by first name, too."

"Oh," Nano says.

Mai shakes her head. "As for Mio… after the first couple of weeks, I believe."

_Three months._ Nano's eyes widen. _That's slow, isn't it._

"However, prudence is good," says Mai.

"Oh." Nano looks at the back of Mai's head. "That's good, then, Mina— Mai-san."

"However, efficiency is also good," says Mai.

"Ehhh…" Nano sighs.

"On the other hand, is also good."

"Huh?" Nano blinks.

"On the other hand, is good."

"Eh…" Nano closes her eyes.

"On the other hand, is preferable."

"What are you talking about?" Nano asks.

"Nes yo," replies Mai.

"Ehh…" Nano sighs.

* * *

After they reach their campsite and set up, it's already well after dark.

Finally, they flick on their lamp and aim it towards Mio and Yukko in the south, who have had their lamp on for the past 20 minutes at the very least.

"Why don't you go first, Min— Mai-san?" suggests Nano. "I'm sorta unsure of my actions, so maybe I can watch you do it first."

"This is fine." Mai takes a seat on the rocky earth and focuses her attention on the light in the distance.

Nano sits cross-legged next to Mai, watching the girl carefully.

The light in the distance turns off. Mai blinks, and then turns off their lamp as well.

"Whoa… dark." Nano blinks.

They sit in the darkness for a while.

Then, the light in the distance blinks on. Mai reacts immediately, flicking on their lamp as well. Then, the light in the distance quickly blinks off.

Mai stares in the distance. "I hope they realize that turning off their lamp like that isn't necessary."

"Huh." Nano nods, already taking some mental notes about the first attempt.

The light in the distance blinks on, but then quickly dims and then rapidly fluctuates in brightness.

"Hm?" Nano points in the distance.

"These lamps have focused beams," Mai explains.

"Huh?..."

"So it'd look like that when the lamp is pointed in different directions."

"Oh…"

The light blinks off. Mai reaches over and flicks their lamp off as well.

Then, the light blinks on again and Mai flicks theirs on as well. Quickly, the distant light blinks off again.

"You'd better not fall asleep," Mai says as the distant light begins wavering in luminosity again.

"Urk…" Nano blinks. It's true. Just a moment ago, her eyelids had been beginning to feel heavy. She rubs her eyes. "Well, that _was_ a very interesting… er… hike?..."

"We'll definitely be having more physically strenuous activities in the future," Mai says.

"Uh… ouohm…" Nano makes a noise as the distant light blinks off. "I see."

Mai flicks their lamp off.

The distant light turns on, and then Mai immediately flicks their lamp on. This time, however, the distant light remains on.

"They finally realized it," Mai nods.

* * *

Despite Mai's insistence on staying awake, Nano is extremely tired, so finally Mai caves in and lets Nano nap for a while.

The two lamps 10 kilometers apart are blinking on and off at a rapid rate, with little pause in between.

"Is she getting impatient," Mai mutters as she continues to flick the lamp on and off, unperturbed.

Each individual trial is starting less than 1 second after the end of the previous trial.

"Machigainai mitai desu ne," Mai says aloud in a soft voice. "It's her. So, what is the meaning of this, Yukko?" Mai actually sounds a bit amused. "Why the rush?"

From an outside observer, it would seem that Mai is flicking the switch on her lamp at the exact moment that the light in the distance blinks on.

Mai has a faint smile on her face. It's really faint, though.

Then, after one particular trial, the distant light stays on. And stays on.

"Tired out, Yukko?" Mai turns around, putting a hand on Nano's shoulder.

Nano wakes up.

"You wanted to go soon?" Mai asks.

"Uh… mn," Nano nods, yawning. "What's going on right now?"

"Their light has been on for a long time now," Mai says, face expressionless.

"Huh? Really?..." Nano nervously looks at the hill in distance. "I really hope they haven't gotten into another fight."

Mai just looks at the light in the distance with an impassive expression.

"Uh… Mi— Mai-san, what are you doing?" Nano turns to Mai, who has just started rapidly flicking the lamp on and off.

"I'm signaling to them that we want to switch roles now," Mai says.

_Ima ro–ru o h__enkou shimashou._

"I see," Nano says.

Mai repeats the message several times as they wait for a response.

Nano yawns again, stretching. "Actually, can I first watch you do A for a while before I do it?"

"No issues," says Mai. "We'll be here all night."

The distant light suddenly flickers four times.

"I think they've understood," says Mai.

"I'll get the notebook then, Mai-san," says Nano.

Mai nods.

They do end up doing this well into the night. They obtain lots of data. Way more data than they actually need, in fact.

* * *

日常 - nichijou, Arawi Keiichi

* * *

A/N: Remember, Mai (supposedly) has experience, and Nano is a robot, so she probably won't get hurt too much if she falls 700 meters off a cliff or waterfall or something.


	3. Nakamura

A/N: Selryam: Yes, it was a physics test.

* * *

日常 - nichijou, Arawi Keiichi

* * *

Piercing blue eyes snap open with glaring determination.

_Today's the day that I capture you, Shinonome Nano!_

Nakamura looks determined. Even more so than usual.

_My previous schemes have failed, but that was because they were a bit spontaneous. Not very well thought through._

* * *

_Behind the school gymnasium._

Nano fell into the hole in the ground with a surprised cry.

_Clang!_

The hole was too narrow to allow both Nano and her winding key to fall all the way in.

Nano looked around in surprise. "Wh… who did this?" she asked nervously.

No one answered. Nakamura remained hidden in the bushes, grimacing. _The key! I didn't plan for that… I've failed._

* * *

_However, I began planning this scheme well over two weeks in advance!_

Nakamura looks through her binoculars at the two girls hiking in the distance. The science teacher is currently lying low on an outcrop high above and distant from the asphalt path.

_Coming this far from civilization gave me the perfect opportunity. There won't be any bystanders that might get in the way._ Nakamura grins._ I just need to eliminate that Minakami girl, and there'll be no trouble!_

Nakamura frowns. _That implication wasn't intentional. Well,_ obviously_, I'm not going to kill Minakami. That would be foolish. No, I will just immobilize the two of them, and then separate Shinonome from her. That is all. _

Nakamura moves the binoculars down the path. _Good. It looks like they're approaching key location C. Time to initiate phase 1._

Just about a hundred meters down the path, there's a pitfall trap set up. It's cleverly disguised with leaves and branches. All of the debris is well hidden, too. The asphalt that Nakamura drilled up when making the hole is safely tucked behind a large boulder, so there should be no suspicious signs.

_Yes!_ Nakamura grins excitedly. _Almost there…_

Abruptly, the two girls stop walking. They pause there for a moment. Then, they turn to the right and start walking away from the path.

_What!?_ Nakamura exclaims.

The two girls are totally going around the pitfall trap.

_Curses. _Nakamura's eyes narrow. _Nevertheless, I planned for this eventuality. There was always the distinct possibility that Minakami or Shinonome would circumvent that section of the path. For whatever reason._

She grins. _Well then. Phase 2 should more than make up for the failure of phase 1._

Minakami begins climbing up the rock face in the distance.

_What!?_ Nakamura's eyes are wide open. _She's actually climbing up over that?_ _If they make it to the top, they're going to end up skipping 600 meters of the winding mountain path. They'll completely bypass traps 2 through 6!_

Nakamura shifts her binoculars to the path at the top of the distant rock face, grimly smiling. _Still, I accounted for Minakami's eccentric abilities._ _No need to panic yet. There was a sturdy tree just a hundred meters beyond the point at the top of the rock face. There, I constructed a snare that will leave them hanging upside-down. There's no reason why that would fai—_

Minakami begins veering away from the path again.

_Drat!_ Nakamura exclaims. _Is she seeing through all of my traps? No… That's impossible. _

She sits upright and flips through the notebook lying on the ground in front of her.

_They don't seem to take to the path very much…_ Nakamura sweats. _Most of my traps were constructed around the premise that Shinonome and Minakami walk along the main path. Not good…_

The science teacher looks up and sees the two girls climbing up another distant cliff.

She flips to a scaled bird's eye view diagram of the mountain path. She traces her finger over it. _With that climb, they'll bypass traps 9 through 13. What should I do?..._

She looks up again and sees the two girls slowly making their way across a shaky rope bridge. _Why are they doing that?_ Nakamura looks puzzled. _I saw their plans. That route takes them in the opposite direction of their destination. Did they change their plans at the last minute? That would completely derail my scheme. This is bad…_

She frantically flips to a larger map. On that page, there's a complex colour-coded diagram of various routes.

_If they continue in that direction, they'll enter the Western mountain route. Trap coverage is minimal there. _She quickly slides her finger across a twisting blue path. _If they take that bridge, they'll end up in that network. However, if they take that bridge, they'll be end up in the return path system… Hm…_

Nakamura is already pulling an electronic gadget out of her backpack and twisting up wires. _So… This is probably the best option._ She sets the frequency to _10526.00_ and then twists the switch.

**Boom.**

In the distance, a large quantity of dynamite detonates, blowing up a faraway cliff and knocking loose tons of boulders. The avalanche of rocks descends, knocking out a wooden path, a couple of trees, and one large bridge.

_The elimination of those routes should nudge Shinonome and Minakami back onto track._ Nakamura takes out a pen and crosses out three waypoints on her map. _Hopefully, that did the trick._

The two girls walk across the asphalt path at a 90 degree angle.

_If they continue with these cliff climbs, they should get close enough to location M for trap 27 to succeed._ Nakamura sets the frequency on her electronic gadget to _08624.10_. Her hand is poised, ready to turn the switch.

_Okay, now._

With a flick of the wrist, the switch is turned. Nothing happens.

A few seconds pass.

Nakamura doesn't look deterred at all. _Good, good._ She grins ecstatically. _As of this moment, the air there should be rapidly filling with sleeping gas!_

She looks at her watch. _According to my preliminary experiments, within 12 seconds, gas levels should be sufficient to knock out Minakami. It's very likely that the gas will be ineffectual on Shinonome, but that's fine. Phase 2, the elimination of Minakami, will be cleared. Based on what I have observed of Shinonome's personality, it should be trivial to capture the robot once the other girl is out of the way._

Nakamura doesn't look away from her binoculars. _I've really got to stop calling it 'elimination', though. It has misleading connotations. Maybe I should call it something more… blegh-y, like 'detainment', or 'restraint' or something. That would be better. _

_Wait, something's wrong._

The science teacher looks at her watch. _It's already been 20 seconds. Why aren't they falling over yet?_

She peers through her binoculars with a sharp eye. _It doesn't look like they're wearing gas masks. Why would they be wearing gas masks anyway? But why isn't the gas taking effect? I've tested this many times! The dispersers should be functioning perfectly. What gives?_

Nakamura's hair blows in the wind.

Her eyes widen dramatically. _The wind!_

She licks her finger and holds it up at arm's length. _Darn it, the wind's very strong today. I forgot to account for air resistance! I always forget to account for air resistance._

She collapses back on the ground again and looks through the binoculars at the two girls in the distance. _It's blowing in the wrong direction. All of the gas is being blown away from those two!_

The two girls continue walking up the steep hill.

_Come on, wind. Change! Hurry! If they keep walking, they're going go out of range…_

The two girls walk out of range.

_Blast._ Nakamura sits up, tousling her hair. _Well, that failed._

She eyes the electronic gadget.

_08624.10_

_Well, no sense in wasting it all, I guess._ Nakamura twists the switch back into its starting position. In the distance, all seven of the gas dispensers close up.

_Now, what to do next?..._ Nakamura sits pensively, looking over the notebook page.

She picks up her binoculars and searches for the two girls again. _Where are they likely to go next? Hm… Whoa what. Are they crazy? What is the meaning of theirs cation what wait what?_

The two girls are slowly stepping onto a very narrow ledge with a very steep drop.

_What is the meaning of this? Most likely, Shinonome won't be in danger because of her robotic construction. She's likely to survive the fall, if it occurs. But Minakami? Is she taking advantage of Shinonome's being a robot?— No, she can't possibly know that she's a robot… No wait, she has one of the highest marks in my class. She's clearly smart enough to deduce something as obvious as that. No, it still doesn't explain… No, but… No, well… No however… No… No… No… No. No. No._

Nakamura clutches her head. _Agggh, _Infinite_ loop!_

She picks up the binoculars again. _Maybe the tranquilizer darts will—_

The spectacled girl begins climbing up the vertical rock face.

_No, they're going the wrong way, _again!

Nakamura puts her hand to her mouth. _What to do in this situation? They're circumventing all of my traps._

She flips to near the end of the notebook. _Hm. Contingency plan #15B. Complete circumvention of all traps by both female students. Let's see…_

She slowly slides her finger down the page. _No way._

_It's blank!_ Nakamura cries, throwing her arms in the air. _I didn't have time to complete all of the contingency plans! This isn't useful at all!_

The two girls are walking down a steep staircase in the distance. Their route is gradually taking them closer to Nakamura.

_Calm down, Nakamura._ Nakamura's face hardens. _Panic won't get you anywhere. For a scheme planned out to this extent… Failure is unacceptable. Right._

Nakamura closes her eyes. _I still don't know what to do._

The two girls continue walking in the distance. They're at a significantly higher altitude than they were at the beginning of Nakamura's scheme.

The science teacher leaps forward, slamming her hands on the ground. _No, wait!_

The two girls are close enough now for Nakamura to just barely see them without the help of binoculars.

_Yes, they're approaching the waterfall!_

With a dramatic arm flick, Nakamura flips through about forty pages back to the beginning of her notebook. _I have traps 52 through 56 centered around that area. Okay, this will work._

Nakamura lowers her head. _If they attempt to travel upstream to circumvent the rapidly flowing stream, trap 52 will ensnare them in a net. The path is completely riddled with triggers. It's impossible for them to walk that way without setting off at least one._

The two girls halt in front of the rapidly flowing stream. The girl with the long hair appears to be surveying the scene, and the other girl is hunched over, panting.

_That stream is actually not that deep. If they decide to try and wade across the river, foolish as that would be, trap 54 will stick them on the spot. _Nakamura grins. _I have smeared the entire middle area of the stream with waterproof adhesive._

_Once trap 54 has accomplished its goal, trap 55 will activate. The mechanism I set up beforehand will dam up the stream a ways upstream. The area of the stream with the adhesive will quickly drain out over the waterfall, giving me a nice dry piece of land to work with. Next, the sack (made of extremely tough material) will be thrown over Shinonome. Finally, the ground below Shinonome will open up and then she will be tossed into the cavern I have dug out below the stream— secret base # 2._

The long-haired girl pulls something from her pack.

_And, if they cross using the log… well, heh heh._ Nakamura smirks. _Unbeknownst to them, that "log" isn't a log at all, but rather an ingenious (and expensive!) trapping device that I invented. Trap 53— Once Shinonome has crossed the stream, a net will shoot out of the ground at the end of the log. Once they are ensnared in the net, a paralyzing agent will burst out in all directions, immobilizing the two. Once they are paralyzed, the grabbing arm will emerge from the log, grab Shinonome, toss her into the storage compartment, close up again, turn into a submarine and then swim upstream to deposit Shinonome in secret base # 3. _

Nakamura nods. _And if they decide to use a rope to cross at any location along the stream, especially over by the waterfall, trap 56 will activate. All of the rocks on either side of the stream will crumble and collapse, dropping the rope into the water, along with Shinonome and Minakami. They'll flow right off the edge of the waterfall! There, a wide elastic fabric net will pop out and catch them. Then, another net— a rope one— will spring out and restrain Shinonome and Minakami. Finally, the elastic net will retract, depositing the two of them into secret base # 2._

She chuckles. _Perfect. I'll finally capture you, Shinonome Nano._

The spectacled girl kicks the log off of the waterfall.

Nakamura's jaw drops. _Whaaaaa!?... _

She face-palms herself. _Crap! The automatic sensors failed! And I didn't notice it in time to activate the manual trigger!_

The "log" shatters onto the rocks below, sending hundreds of thousands of yen of delicate machinery flying in all directions.

_Noooo~!_ Nakamura weeps.

The two girls begin walking towards another cliff.

_Get a grip on yourself. Dwelling over my failures is useless. I need to focus 100% of my attention on capturing Shinonome!_

Nakamura grins nervously. Sweat is trickling down her face. _This isn't over yet. I still have several more things I can try. I swear, by the time this day's done, I will have you in my possession, Shinonome Nano!_

She flips to the map again. _The bottleneck in their route is that bridge. If I can knock that out, I can herd them over to those two heavily trapped areas. Yes, this can work._

_I'll do that first._ She sets the wireless transmitter to _08585.24_ and then turns the switch.

**Boom.**

_Now, the tree should have fallen over and it should obstructing the bridge entrance._ Nakamura picks up her binoculars, and points it upwards. _With their unconventional cliff-climbing travel, they'll most likely end up circumventing traps 57 through 68, so there's no point in trying to catch them with those._

The two girls begin descending a cliff. Nakamura follows their progress with her binoculars.

_I'll focus all of my attention an traps 69 through 73. That's their weak point— They'd have to circumvent the main bridge. I'll get them. And even if the tree obstacle fails, I have traps 74 and 75 as contingency plans._

Nakamura pulls out two other wireless transmitters. She sets the three of them to _13000.00_, _13100.00_, and _13200.00_ respectively. _I clearly can't depend on the automatic triggers. I'll activate the traps manually when the time comes._

The two girls pause in front of the bridge.

Then, they walk right up to the giant fallen tree that's blocking their way and start climbing over it.

Nakamura's eyes shoot wide open. _They're climbing over it!_

With both hands simultaneously, she quickly switches two of the wireless transmitters to _13500.00_ and _13501.00_.

_Trap 74— An airbag-like mechanism shoots out of the tree trunk, inflating in milliseconds and throwing them right off the log. Giant nets will then shoot out, catch them, and then toss them into secret base # 3._

She reaches over and sets the third wireless transmitter to _13600.00_.

_Trap 75— The wooden planks on the bridge floor will open up, dropping them towards the river below. The same aforementioned nets will shoot out, catch them, and toss them into secret base 3._

The science teacher carefully watches the two girls above her with her binoculars. They reach the summit of the log.

_NOW!_

Nakamura turns the switch on the _13500.00_ transmitter.

Nothing happens.

_NANI!?_

Nakamura's eyes are wide open.

Next, the two girls climb down the other side of the log and land on the bridge.

…_NOW!_...

Nakamura turns the switch on the _13600.00_ transmitter.

Nothing happens again.

_Nande!?_

Nakamura turns the _13600.00_ switch repeatedly in disbelief.

_NAZE!?_

No effect.

The two girls walk the entire length of the bridge without anything happening.

_Why didn't the traps go off!?_ Nakamura is sweaty and panting for breath.

The two girls are now walking along a path that's several hundred meters higher in altitude than Nakamura's hiding place.

Nakamura's face is severely grim. _I never thought that they'd get this far. Traps 76 to 85 are the last ones I have in place. If none of those work… then…_

Something bright yellow flies off of the cliff several hundred meters above. It falls through the air and hits the ground only several paces away from Nakamura.

Nakamura starts hyperventilating, staring at the yellow package with her eyes wide open in horror.

_Pl…Pl…It's a plastic explosive!_

Putting her survival above all else, Nakamura shoots off of the ground and sprints for cover, leaving all of her equipment behind.

She dives behind a corner and scrunches up into a ball, plugging her ears.

Nothing happens.

Several seconds pass.

Nothing happens.

Several minutes pass.

Nothing happens.

A further twenty-one minutes elapse.

Nothing happens.

Nakamura cautiously tosses a rock out into the open, just on the off chance that the plastic explosive is motion-activated.

Nothing happens.

Nakamura cautiously peeks around the corner, dripping with sweat. She immediately drops back into cover, just on the off chance that the plastic explosive will detonate upon detecting Nakamura with face-recognition software.

Nothing happens.

Finally, the science teacher slowly crawls out and approaches the yellow package.

_It doesn't appear to be a plastic explosive…_ Nakamura sighs in relief. _It's a package._

She cautiously unwraps it. The first thing that she spots is a note.

Nakamura inhales sharply.

Nakamura-sensei, stop stalking us.

Otherwise, I will obtain a restraining order from the police.

Minakami

Also inside the package are about twelve wireless receivers.

_Minakami Mai…_ Nakamura breathes. Her forehead glistens with sweat. _I underestimated her. She disabled all of the traps from 74 to 85. _

Nakamura puts her hand to her forehead as if she's getting a headache. _How did she know those traps were there? And no, how did she even have time to remove all of these traps!? She didn't have time! I've been watching her this entire time! There's no way—_

The science teacher's eyes widen as she gasps. _Ohhhh…_

* * *

_2011__年 __10__月 __7__日_

Mai hurried out of the classroom as soon as the bell rang.

_She was in a hurry to get somewhere as soon as the bell rang on that Friday._

Nakamura held up a payphone, waiting for somebody on the other end to pick up.

_When I called her home that evening to discreetly ensure that there were no last-minute changes to their plans, she wasn't at home._

Nakamura stood at a payphone, this time calling a different number.

_When I called her cell phone, it wasn't within reception range. Thus, the call couldn't be connected._

* * *

Metaphorical lightning flashes across her eyes as realization strikes Nakamura. _The day before!_

_Minakami hiked out to the mountain the day before to make sure that the route was okay. This is why I couldn't call her. There's no reception here. The pre-route checking is a responsible thing, and typical of Minakami. I should have foreseen this. She must have come across my traps on that day, and taken steps to disable all of them._

Nakamura clenches her fist. _I didn't count on Minakami coming across the traps on the day before. At that point, not all of the traps were completely armed yet._

She picks up one of the wireless receivers. The number _83_ is inscribed on it. _Also, I probably shouldn't have sequentially numbered all of the receivers. This made it extremely easy for Minakami to ensure that all of the traps had been removed. Curse you, labeling OCD tendency of mine!_

Nakamura looks up. The two girls are now completely out of view. _What should I do now? Should I continue to follow them and perhaps attempt to manually capture Shinonome?_

…_**!restraining order!…**_

This part of the note blasts itself into Nakamura's awareness.

She gulps, pulling on her shirt. _The principal will be very upset if he learns of a restraining order being enacted against me. He may even fire me for poor conduct! That would be extremely detrimental to my pursuit of Shinonome. _

Nakamura shakes her head. _No, I must avoid causing this restraining order at all costs. In the future, other opportunities will present themselves. No need to rush. I'll just need to make sure that Minakami is nowhere near Shinonome when I try to capture her again._

With that, Nakamura packs up her things and leaves.

* * *

日常 - nichijou, Arawi Keiichi


	4. After

日常 - nichijou, Arawi Keiichi

* * *

Galileo speed of light (c) experiment recreation. 2011年10月8日（土曜日）

17:52 JST - Experiment Trial 01. (Timers: Mio & Yuuko.)

_Elapsed Time (__秒__):_

0.36 | 0.15 | 0.13

0.29 | 0.18 | 0.16

0.24 | 0.17 | 0.16

0.22 | 0.15 | 0.14

0.16 | 0.16 | 0.16

0.18 | 0.14 | 0.15

0.17 | 0.15 | 0.14

0.14 | 0.17 | 0.15

0.16 | 0.18 | 0.12

0.13 | 0.15 | 0.13

0.19 | 0.16 | 0.11

0.14 | 0.14 | 0.12

0.16 | 0.16 | 0.11

0.15 | 0.18 | 0.10

0.17 | 0.17 | 0.13

0.18 | 0.15 | 0.12

.

18:41 JST - Experiment Trial 02. (Timers: Mai & Nano)

_Elapsed Time (__秒__):_

0.41 | 0.37 | 0.32 | 0.72

0.67 | 0.42 | 0.37 | 0.34

0.57 | 0.34 | 0.35 | 0.48

1.18 | 0.28 | 0.32 | 0.28

0.42 | ... ... | 0.27 | 0.27

0.38 | 0.38 | 0.29 | 0.31

0.32 | 0.43 | 0.22 | 0.24

0.35 | 0.38 | 0.28 | 0.20

0.29 | 0.41 | 0.26 | 0.34

0.32 | 0.37 | 0.36 | 0.56

0.38 | 0.57 | 0.38 | 0.85

0.31 | 0.28 | 0.19 | 0.69

0.28 | ... ... | 0.35 | 1.30

0.34 | 0.48 | 0.33 | ... ...

0.24 | 0.32 | 0.48 | 0.96

0.28 | 0.38 | 0.52 | ===

.

19:30 JST - Experiment Trial 03. (Timers: Mio & Yuuko)

0.24 | 0.12 | 0.17 | **N**

0.23 | 0.14 | 0.14 | **A**

0.18 | 0.17 | 0.16 | **N**

0.25 | 0.15 | 0.12 | **O**

0.14 | 0.20 | 0.13 | **l**

0.19 | 0.16 | 0.19 | **l**

0.21 | 0.19 | 0.20 | **V**

0.15 | 0.17 | 0.17 | …

0.19 | 0.18 | 0.18 | …

0.15 | 0.16 | 0.16 | …

0.24 | 0.12 | 0.16 | …

0.21 | 0.14 | 0.17 | …

0.14 | 0.17 | 0.20 | …

0.13 | 0.12 | 0.13 | …

0.16 | 0.13 | 0.14 | …

0.17 | 0.15 | 0.16 | …

.

.

.

.

.

Yukko flips the page, frowning.

Mai sits impassively in front of Yukko.

"You sure you didn't cheat or something?" Yukko grumbles.

"I won," Mai says simply.

"Uh…" Yukko sweats nervously, flipping through the pages.

Mai tilts her head, prompting Yukko to admit her defeat.

"Mediator!" Yukko shouts, slamming her hands on the desk as she turns around.

"No, you definitely lost, Yukko," Mio says, crossing her arms. "Stop being so stubborn. There's no data fudging that will change the outcome."

"Geh…" Yukko sighs. A few seconds pass. "Fine… You won, Mai-chan. I'll buy you a juice."

Mai closes her right hand in victory, smiling a little.

"But I'll win next time!" Yukko declares.

Mai shrugs.

* * *

**日常 ****- nichijou, Arawi Keiichi**


End file.
